I've done a bbm and serpentine belt conversion on my eb and now it idles really high, 2000 rpm high. If I unplug the isc it settles down to where its meant to be. I've taken the isc off and cleaned it and tried resetting the computer but its still idling way to high. Any ideas what's going on and how to fix it? I've done a search but can't seem to find anyone with this specific problem.

It sounds like the ECU is signalling the ISC to stay wide open all the time. What ECU are you using? It could be the ISC driver in the ECU not working properly. Borrowing another ECU should help narrow it down.

first check for vacuum leaks, then adjust your base idle..
normally if you unplug the isc it should pretty much stall or just idle..

if there are no leaks, unplug the isc and lower the idle via the screw untill it gets to 500rpm or just stalls, then plug the isc back in and see how it goes...